? about tire diameter size (od) and performance

[xcivicx]

for 6speed owners that have increased tire outside diameter size. stock size is about 25.3 and wondering if going to 26" or bigger will hurt drivability. thinking 225 45 18 or maybe 235 45 18

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[SCOPESYS]

for 6speed owners that have increased tire outside diameter size. stock size is about 25.3 and wondering if going to 26" or bigger will hurt drivability. thinking 225 45 18 or maybe 235 45 18

I am still trying to get a grip on this..

I am trying to increase the sidewall height to get a smoother ride on bad roads.

Keeping overall wheel+tire diameter the same, if I drop down to 17" rims from 18", I gain 0.5"

If I keep 18" (may be forced to do so on 2018 SI - bigger brakes), and increase wheel Radius by 0.5", I get the same 0.5" increase in sidewall, but a bigger diameter wheel ===> low reading speedometer, and possible wheel rubbing under certain circumstances.

If I do both, 17" and increase tire diameter, I can gain 1" on the sidewall, but I assume I loose some handling .. which really may not be a factor if driving in a less extreme way on bad boards.

Realistically, with non extreme driving, how much can I reasonably be expected to be able to increase the wheel Diameter, before having issues.

I would even consider retrofitting the smaller 2017 Brakes, if that would allow for 17" rims.

 

[xcivicx]

i'm mainly thinking about the acceleration aspec. i remember putting too big a tire on a mini truck, and finding out how gutless it became taking off in first. almost certain a 235 45 18 will fit on a stock height hatch. and i am going for some sidewall is the point

 

[Captaindicki]

I replaced the stock Goodyear all season with same size Michelin PS4s summers (235/40/18). Even though the specs are labeled the same, the Michelin summers do have a chunkier sidewall compaired to the Si stock all seasons. Also the rated rotations per mile are a few less with the Michelin summers compaired to my originals...hence taller

 

[racer]

What is your reason to go to a taller tire? Ground clearance? slower acceleration? Lower revs when cruising on the highway? Trying to insulate against potholes and bad roads?

Ideally you would want to keep a close OD to maintain current drive ability.

17"s will fit on an Si.. You could do a "-1" upgrade.. from a 235/40-18 down to a maybe a 225/45 or 225/50-17 and keep a similar OD but have a slightly taller sidewall. A 215/50-17 is a perfect match.

https://tiresize.com/calculator/

 

[xcivicx]

to put it simply i like the idea of more sidewall for rough roads, will going 1 inch taller (26.3 with 245 45) hurt my first gear take off on a hill. i live on a steep hill. i am thinking no as the civic has enough HP to compensate for what extra power to start off. 0 to speeds i'm not worried about, passing acceleration maybe.

 

[xcivicx]

Ok just put some 26 inch tires on, and yes they affect your acceleration performance. But not so much as you would care. The next size I was thinking about (26.3) might have taken it passed the not caring part.

few day later i'm thinking now most would care, for me i'm finding it a much different car to drove now. accelerates like its much heaver.

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